/*******************************************************************************
* SAT4J: a SATisfiability library for Java Copyright (C) 2004-2008 Daniel Le Berre
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU Lesser General Public License Version 2.1 or later (the
* "LGPL"), in which case the provisions of the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of the LGPL, and not to allow others to use your version of
* this file under the terms of the EPL, indicate your decision by deleting
* the provisions above and replace them with the notice and other provisions
* required by the LGPL. If you do not delete the provisions above, a recipient
* may use your version of this file under the terms of the EPL or the LGPL.
* 
* Based on the original MiniSat specification from:
* 
* An extensible SAT solver. Niklas Een and Niklas Sorensson. Proceedings of the
* Sixth International Conference on Theory and Applications of Satisfiability
* Testing, LNCS 2919, pp 502-518, 2003.
*
* See www.minisat.se for the original solver in C++.
* 
*******************************************************************************/
package org.sat4j.tools;

import java.io.Serializable;

import org.sat4j.core.VecInt;
import org.sat4j.specs.ContradictionException;
import org.sat4j.specs.ISolver;
import org.sat4j.specs.IVecInt;

/**
 * Very simple Dimacs array reader. Allow solvers to read the constraints from
 * arrays that effectively contain Dimacs formatted lines (without the
 * terminating 0).
 * 
 * Adaptation of org.sat4j.reader.DimacsReader.
 * 
 * @author dlb
 * @author fuhs
 */
public class DimacsArrayReader implements Serializable {

    private static final long serialVersionUID = 1L;

    protected final ISolver solver;

    public DimacsArrayReader(ISolver solver) {
        this.solver = solver;
    }

    protected boolean handleConstr(int gateType, int output, int[] inputs)
            throws ContradictionException {
        IVecInt literals = new VecInt(inputs);
        solver.addClause(literals);
        return true;
    }

    /**
     * @param gateType
     *            gateType[i] is the type of gate i according to the Extended
     *            Dimacs specs; ignored in DimacsArrayReader, but important for
     *            inheriting classes
     * @param outputs
     *            outputs[i] is the number of the output; ignored in
     *            DimacsArrayReader
     * @param inputs
     *            inputs[i] contains the clauses in DimacsArrayReader; an
     *            overriding class might have it contain the inputs of the
     *            current gate
     * @param maxVar
     *            the maximum number of assigned ids
     * @throws ContradictionException
     *             si le probleme est trivialement inconsitant
     */
    public ISolver parseInstance(int[] gateType, int[] outputs,
            int[][] inputs, int maxVar) throws ContradictionException {
        solver.reset();
        solver.newVar(maxVar);
        solver.setExpectedNumberOfClauses(outputs.length);
        for (int i = 0; i < outputs.length; ++i) {
            handleConstr(gateType[i], outputs[i], inputs[i]);
        }
        return solver;
    }

    public String decode(int[] model) {
        StringBuffer stb = new StringBuffer(4 * model.length);
        for (int i = 0; i < model.length; i++) {
            stb.append(model[i]);
            stb.append(" ");
        }
        stb.append("0");
        return stb.toString();
    }

    protected ISolver getSolver() {
        return solver;
    }
}
